Merge topic 'perf-from-callgrind'

318550c7 CheckCollapsePath: add more test cases
71a6de42 CollapseFullPath: refactor the overloads to share implementations
68807138 CollapseFullPath: prefer .empty() to .length() == 0
55d1d6ab CollapseFullPath: reserve space for components
3b46b7c0 ConvertToUnixSlashes: bail early on empty paths
5dd87350 ConvertToUnixSlashes: remove pos1
342d69a4 ConvertToUnixSlashes: short-circuit on hasDoubleSlash
22b189b0 ConvertToUnixSlashes: remove escaped space logic
...

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !86